1. Field of the Invention
The present invention relates to a bimorph element, a bimorph switch, a mirror element including the bimorph element, and a method for manufacturing these. The present application also relates to the following application, the contents of which are incorporated herein by reference if applicable.
A Japanese Patent Application No. 2004-254810 Filed on Sep. 1, 2004.
2. Related Art
Bimorph switches have been recently known as an example of micro devices that are manufactured by a semiconductor process. The bimorph switches have two layers with a different thermal expansion coefficient, and are bent by means of heating these layers by the heater. Since a traveling contact is provided on the bent portion and a fixed contact is provided at a position facing the traveling contact, a switch for switching ON and OFF for electric connection can be formed, as disclosed, for example, in Japanese Patent Application Publication No. 2004-55410 and WO2004/024618.
However, in a bimorph element such as bimorph switches, since internal stress of a silicon oxide layer constituting one side of two layers changes over time, there has been a problem that the shape of element changes over time. For this reason, there has been a problem that input power to give desired displacement to the bimorph element is different every device.